Plate fin type heat exchangers generally comprise a plurality of plates, and a plurality of fins extend between and are secured to each adjacent pair of plates. The fins are secured to the plates by brazing, welding, diffusion bonding etc. The fins are defined by corrugated plates. In plate fin type heat exchangers the fins define passages for the flow of fluids to be put into heat exchange relationship.
Primary surface plate type heat exchangers generally comprise a plurality of plates, and a plurality of spacers extend between each adjacent pair of plates to separate the plates. In primary surface plate type heat exchangers the plates define passages for the flow of fluids to be put into heat exchange relationship.
A plate fin heat exchanger or primary surface plate heat exchanger is capable of being closely positioned around an engine, such as a gas turbine engine, if the heat exchanger is in a spiral form. These spiral heat exchangers will provide advantages of being cheaper to manufacture, produce lower thermal stresses and provide blade containment if positioned around a turbine of a gas turbine engine. However previous attempts to manufacture a spiral heat exchanger did not result in a simple practical method for supplying the fluids to and removing the fluids from the heat exchanger.